The described subject matter relates generally to the field of additive manufacturing. In particular, the subject matter relates to operating an energy beam to facilitate additive manufacturing.
Additive manufacturing refers to a category of manufacturing methods characterized by the fact that the finished part is created by layer-wise construction of a plurality of thin sheets of material. Additive manufacturing may involve applying liquid or powder material to a workstage, then doing some combination of sintering, curing, melting, and/or cutting to create a layer. The process is repeated up to several thousand times to construct the desired finished component or article.
Various types of additive manufacturing are known. Examples include stereo lithography (additively manufacturing objects from layers of a cured photosensitive liquid), electron beam melting (using a powder as feedstock and selectively melting the powder using an electron beam), laser additive manufacturing (using a powder as a feedstock and selectively melting the powder using a laser), and laser object manufacturing (applying thin solid sheets of material over a workstage and using a laser to cut away unwanted portions).
In additive manufacturing, conventional apparatus utilize a galvanometer type scanner to melt powder layers in an X-Y linear orientation. This linear path is broken up into smaller sections, called rastering. This causes discontinuity in the scanning paths, and can result in small but significant areas of unmelted powder therebetween, which operate as stress risers in the finished part.